| 摘要 |
925,502. De-airing plastics materials in extrusion apparatus. FRANKLIN RESEARCH & DEVELOPMENT CORPORATION. Dec. 12, 1961 [July 24, 1961], No. 44463/61. Class 87(2). Granular or powdered plastic feed stock for an extrusion machine is freed of air, moisture, &c. in feed apparatus comprising a vertical conduit having a series of evacuated chambers. An uninterrupted supply of feed material is obtained by having two or more such chambers one above the other, only the middle or upper ones being opened intermittently to air for introduction of fresh feed. Provision may also be made for vacuum lifting feed stock from a hopper to the upper evacuable chamber. In the embodiment described, the extruder 20 is fed with material in the chamber 32, evacuable at the pipe 52. This chamber is intermittently fed by material from the chamber 14, also evacuable. The doors 48 and 50 of these chambers are hinged at 66, and open downwards against the stops 116. The upper chamber 14 is filled from the top chamber 70, Fig. 2, 70<SP>1</SP>, Fig. 4, into which material may be drawn from the container 130 by a suction lift (pipe 134, pump 136). Provision is made for automatic control, and for keeping level the surface of the feed in the container 130 by rotating the ribbed plate 150.
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